/*
 * Copyright (c) 2005, Swedish Institute of Computer Science
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 *
 * @(#)$Id: clock.c,v 1.17 2008/12/02 12:44:48 joxe Exp $
 */

#include <io.h>
#include <signal.h>

#include "contiki-conf.h"

#include "sys/clock.h"
#include "sys/etimer.h"
#include "rtimer-arch.h"

#define INTERVAL (RTIMER_ARCH_SECOND / CLOCK_SECOND)

#define MAX_TICKS (~((clock_time_t)0) / 2)

static volatile unsigned long seconds;

static volatile clock_time_t count = 0;
/* last_tar is used for calculating clock_fine, last_ccr might be better? */
static unsigned short last_tar = 0;
/*---------------------------------------------------------------------------*/
interrupt(TIMERA1_VECTOR) timera1(void) {
	if (TAIV == 2) {

		/* HW timer bug fix: Interrupt handler called before TR==CCR.
		 * Occurrs when timer state is toggled between STOP and CONT. */
		while (TACTL & MC1 && TACCR1 - TAR == 1)
			;

		/* Make sure interrupt time is future */
		do {
			TACCR1 += INTERVAL;
			++count;

			/* Make sure the CLOCK_CONF_SECOND is a power of two, to ensure
			 that the modulo operation below becomes a logical and and not
			 an expensive divide. Algorithm from Wikipedia:
			 http://en.wikipedia.org/wiki/Power_of_two */
#if (CLOCK_CONF_SECOND & (CLOCK_CONF_SECOND - 1)) != 0
#error CLOCK_CONF_SECOND must be a power of two (i.e., 1, 2, 4, 8, 16, 32, 64, ...).
#error Change CLOCK_CONF_SECOND in contiki-conf.h.
#endif
			if (count % CLOCK_CONF_SECOND == 0) {
				++seconds;
			}
		} while ((TACCR1 - TAR) > INTERVAL);

		last_tar = TAR;

		if (etimer_pending() && (etimer_next_expiration_time() - count - 1)
				> MAX_TICKS) {
			etimer_request_poll();
			LPM4_EXIT;
		}
	}
}
/*---------------------------------------------------------------------------*/
clock_time_t clock_time(void) {
	return count;
}
/*---------------------------------------------------------------------------*/
void clock_set(clock_time_t clock, clock_time_t fclock) {
	TAR = fclock;
	TACCR1 = fclock + INTERVAL;
	count = clock;
}
/*---------------------------------------------------------------------------*/
int clock_fine_max(void) {
	return INTERVAL;
}
/*---------------------------------------------------------------------------*/
unsigned short clock_fine(void) {
	unsigned short t;
	/* Assign last_tar to local varible that can not be changed by interrupt */
	t = last_tar;
	/* perform calc based on t, TAR will not be changed during interrupt */
	return (unsigned short) (TAR - t);
}
/*---------------------------------------------------------------------------*/
void clock_init(void) {
	dint();

	// clear
	TACTL = TACLR;

	TACTL = TASSEL_ACLK | ID_DIV8;

	/* Select ACLK 12000kHz clock, divide by 4 (3000Hz) */
	TACTL = TASSEL0 | TACLR | ID_2;

	/* Initialize ccr1 to create the X ms interval. */
	/* CCR1 interrupt enabled, interrupt occurs when timer equals CCR1. */
	TACCTL1 = CCIE;

	/* Interrupt after X ms. */
	TACCR1 = INTERVAL;

	/* Start Timer_A in continuous mode. */
	TACTL |= MC_CONT;

	count = 0;

	/* Enable interrupts. */
	eint();

}
/*---------------------------------------------------------------------------*/
/**
 * Delay the CPU for a multiple of 2.83 us.
 */
void clock_delay(unsigned int i) {
	asm("add #-1, r15");
	asm("jnz $-2");
	/*
	 * This means that delay(i) will delay the CPU for CONST + 3x
	 * cycles. On a 2.4756 CPU, this means that each i adds 1.22us of
	 * delay.
	 *
	 * do {
	 *   --i;
	 * } while(i > 0);
	 */
}
/*---------------------------------------------------------------------------*/
/**
 * Wait for a multiple of 10 ms.
 *
 */
void clock_wait(int i) {
	clock_time_t start;

	start = clock_time();
	while (clock_time() - start < (clock_time_t) i)
		;
}
/*---------------------------------------------------------------------------*/
void clock_set_seconds(unsigned long sec) {

}
/*---------------------------------------------------------------------------*/
unsigned long clock_seconds(void) {
	unsigned long t1, t2;
	do {
		t1 = seconds;
		t2 = seconds;
	} while (t1 != t2);
	return t1;
}
/*---------------------------------------------------------------------------*/
rtimer_clock_t clock_counter(void) {
	return TAR;
}
/*---------------------------------------------------------------------------*/
